Nestable containers



Dec. 16, 1969 .P..DAV|S 3,484,018

NESTABLE CONTAINERS Filed Nov. 28, 1967 4 Sheets-Sheet 1 :mmwmm INVENTOR. PA U L DAV I S ATTORNEYS Dec. 16, 1969 P. DAVIS 3,484,018

NESTABLE CONTAINERS Filed Nov. 28, 1967 4 Sheets-Sheet 2 ifi i i ZZZ i \WM QWWMMW INVENTOR.

PAUL DAVIS ATTORNEYS Dec. 16, 1969 P. DAVIS NESTABLE CONTAINERS 4 Sheets-Sheet 3 Filed Nov. 28, 1967 my 2 I3 Ummllllllhr FQG. 3

ILL i F @G. 57 2|3b r INVENTOR. PAUL DAVIS ATTORNEYS Dec. 16, 1969 P. DAVIS 3,484,018

NESTABLE CONTAINERS Filed Nov. 28, 1967 4 Sheets-Sheet 4 INVENTOR. PA U L DAV! S ATTORNEYS nited States Patent O 3,484,018 NESTABLE CONTAINERS Paul Davis, Swampscott, Mass, assignor to Sweetheart Plastics, Inc., Wilmington, Mass. Filed Nov. 28, 1967, Ser. No. 686,080 Int. Cl. B65d 21/00, 3/06 US. Cl. 220-97 4 Claims ABSTRACT OF THE DISCLOSURE A one-piece, thin wall plastic container is provided having an upwardly flared side wall and a transversely extending bottom wall with a stacking ring in the side wall forming internal and external shoulders each being circumferentially undercut and having a radial extent to provide an interference with another when two like containers are nested together with the external shoulders of one resting on the internal shoulders of the next lower container.

BACKGROUND OF THE INVENTION A plurality of nestable plastic containers such as drinking cups are known in the art. Such plastic containers which may be vacuum or pressure formed of thin stock sheet material, frequently employ stacking ring means in the side wall to provide internal and external shoulders so that the external shoulders of one cup rest on the internal shoulders of the next lower cup in a stack. Sufiicient interference is provided by the internal shoulders due to the use of an upwardly and axially inwardly extending stacking ring forming a generally Z-shape in cross section. Many variations of this basic stacking ring means are known in the art and include the use of inturned ridges and projecions of all sorts to form inwardly directed undercuts in the side walls of thin wall plastic containers to provide the necessary interference and permit stacking.

Problems sometimes arise with inwardly undercut stacking ring shoulders when large stacks of containers are shipped and the stacks subjected to severe pressures at ends thereof as by dropping of a stack. In some cases, forces on the stack will tend to jam containers together carrying the external shoulder of one container beyond the interference provided by the internal shoulder of its adjacent container whereupon a wedge action locks the containers together making it extremely difiicult to separate them. In some cases, vending machines are jammed because of the tight interlock between two or more containers in a stack which interlock cannot be overcome by the normal separating apparatus in conventional vending machines SUMMARY OF THE INVENTION A thin wall, integral, plastic container is provided with an upwardly flared side wall and a transversely extending bottom wall. An inwardly extending shelf is provided in the side wall defining a plurality of internal shoulders dimensioned to provide interference to a like container nested in said container with each shoulder having a predetermined circumferential length. A preferably vertical stacking ring extends coaxially with the container and downwardly from the internal shoulders. The stacking ring has a plurality of spaced protuberances preferably extending from top to bottom thereof with each defining a greater circumferential distance at the bottom than at the top whereby a plurality of circumferential undercuts are formed at edges of the shoulders in the shelf to provide the required interference. Preferably the bottom of each protuberance is continuous with an inwardly extending shelf or with the bottom of the container to form ice external shoulders. Thus, in each of the containers of this invention, the internal shoulders which form a shelf on which another container rests are undercut circumferentially and not radially of the container axis.

In another embodiment of the invention, the internal and external shoulders have substantially equal circumferential length and a circumferential undercut is provided in the stacking ring to permit stacking.

In the preferred embodiment, the stacking ring and the outer portions of the protuberances are substantially coaxial and vertically extending. Thus, if one container should be forced within another, one of the two containers tends to deform and be crushed axially and radially whereby no tight jamming into engagement occurs. This feature is important since feeds of conventional vending machines would tend to discharge containers made in accordance with the present invention successively, even if stacks of such containers have been subjected to sever handling shocks and certain of the containers are moved axially with respect to others.

The particular stacking rings and nestable features of containers made in accordance with the present invention have the advantage of a circumferentially extending undercut making the containers of the present invention easier to strip from a mold than conventional radially undercut containers. Moreover, the protuberances provide for air passage between stacked containers enhancing ease of removing one container from a stack of containers.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will be better understood from the following specifications when read in connection with the accompanying drawings in which:

FIG. 1 is a front perspective view of a preferred embodiment of two nested cups of the present invention;

FIG. 2 is a front view thereof with the outside cup shown as transparent;

FIG. 3 is a top view thereof showing portions of the inside cup in dotted outline in two positions about the axis;

FIG. 3' is a bottom view thereof;

FIG. 4 is a cross sectional view taken through line 4-4 of FIG. 1;

FIG. 5 is a cross sectional view taken through line 55 of FIG. 1;

FIG. 6 is a perspective view of an alternate embodiment thereof;

FIG. 7 is a fragmentary front view of an alternate embodiment of the invention showing the novel stacking 11mg;

FIG. 8 is a fragmentary front view of two nested cups of the embodiment of FIG. 7 with the outside cup shown as transparent;

FIG. 9 is a top view of the cup of FIG. 7;

FIG. 9A is a cross sectional view taken through line 9a-9a of FIG. 7;

FIG. 10 is a front fragmentary view of still another cup of this invention;

FIG. 11 is a front view of two nested cups of the embodiment of FIG. 10;

FIG. 12 is a top plan view of the cup of FIG. 10;

FIG. 13 is a front view of still another embodiment of this invention;

FIG. 14 is a bottom view of the embodiment of FIG. 13;

FIG. 15 is a top view of the embodiment of FIG. 13;

FIG. 16 is a fragmentary projection of the stacking ring of the cup of FIG. 1 showing the stacking ring in fiat form;

FIG. 17 is a fragmentary projection of stacking ring of the cup of FIG. 10 showing the stacking ring in flat form;

FIG. 18 is a fragmentary projection of the stacking ring of the cup of FIG. 13 showing the stacking ring in flat form;

FIG. 19 is a fragmentary side view of a container as shown in FIG. 1 but with an alternate embodiment of the stacking ring of this invention; and

FIG. 20 is a top view of the embodiment of FIG. 19.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to the drawings, a thin wall thermoformed plastic drinking cup 10 is illustrated in FIG. 1 having a side wall 11 tapering upwardly and outwardly along its central axis 14 from a bottom wall 12 extending transversely of the cup. The bottom wall preferably has a central dome portion. A stacking ring 13 separates the bottom wall from the upper portion of the side wall which can be straight as shown or provided with decorative or functional, molded or embossed configurations as is known in the art. An inner container 10 identical to cup 10 is shown to illustrate a stacked position of two or more cups.

The cup 10 is preferably of a thin wall plastic such as polystyrene having an over-all wall thickness of approximately 0.0l inch thermoformed from a 0.030 inch thick polystyrene sheet. However, various other plastics such as polyethylene, impact polystyrenes, polypropylene, foam plastics and the like can be used in accordance with the present invention. The containers themselves may have several uses and configuration; thus, cottage cheese containers, bowls, plates and drinking cups can be formed in a variety of sizes.

In the preferred embodiment, the stacking ring 13 is a right cylinder coaxial with the cup axis 14 and lies between the bottom wall 12 and the top of the side wall 11 as best seen in FIG. 1. Above the stacking ring 13 is an inwardly extending preferably horizontal shelf 15 which is substantially circumferentially discontinuous at its inner edge and is defined by a plurality of circumferential extending internal shoulders 16 and spaces 16a. The bottom wall defines circumferentially extending external shoulders 17 and spaces 17a. Spaced protuberances 18 extend from top to bottom of the cylindrical portion of the stacking ring and radially outwardly therefrom.

The protruberances 18 are delimited by side lines 19 which are substantially straight and form the intersections of the protuberances and the cylindrical portions of the stacking ring. Lines 19 are offset from the vertical or a line parallel to the axis of cup 10 by an angle of about 10 to 25 and preferably about 18 so that the internal shoulders 16 are spaced apart by internal generally trapezoidal-shaped notches 13a of the stacking ring portion defined by protuberances 18 as best seen in FIGS. 1-3. The angle of lines 19 defines the amount of circumferential undercut under the internal shoulders with larger angles providing greater interference than smaller angles.

As may be seen in FIGS. 1, 2, 3, 3, 4 and the protuberances 18 extend upwardly and are in fact cylinderlike sections or columns as are the stacking ring cylindrical wall portions which portions are recessed in front view shown at 1311 in FIG. 1. The protuberances or columns 18 are narrower at their tops than at their bottoms to make the resulting external shoulders 17 have a greater circumferential length than the circumferential length of gaps or spaces 16a thus providing the desired interference. Lines 19 are reverse portions of helically extending lines about the stacking ring drawn on a center axis coaxial with axis 14 of the cup. Left and right helical lines are provided. Since right and left helical lines are used as edges of portions 18, sufficient interference is provided by the undercut areas of the circumferential undercuts at edges 19a to prevent jamming action as shown in FIG. 3.

In use of the cups of this invention, when the cups are stacked and two or more containers nested, the lower or external shoulders 17 which each have a longer circumferential length than each of the upper spaces 16a between shoulders 16 rest on the internal shoulders 16 as shown in dotted outline in FIG. 3 and in FIGS. 4 and 5. Thus, shoulders 15 of the shelf 15 prevent downward travel of the inner container and the undercuts 1% below each end or edge of the internal shoulders 16 assure that no matter what the angular position of the inner cup about its axis with respect to the outer cup, the external shoulders 17 of one cup cannot pass beyond the internal shoulders 16 of an adjacent cup. Moreover, since the external walls of protuberances 18 are parallel to the stacking ring wall 13 and both are vertical or parallel to the axis of the cup, when substantial forces are exerted on ends of a stack of cups, there Walls will tend to collapse axially and the inner container is deformed radially allowing passage of the inner container beyond the internal shoulders. Locking of the cups together is prevented since there is no inwardly and upwardly directed stacking ring which would tend to interlock the undercut with a crushed end of an inner container and thus, slightly crushed ends of cups can be easily separated by hand or Turning now to FIG. 6, an alternate embodiment 30 is shown wherein like numerals represent like parts. In the embodiment of FIG. 6, the stacking ring, protuberance and shoulder structures are identical to that described above with reference to FIG. 1 except that instead of lying at the bottom of the cup, these members are placed further up along the side wall of a cup. It should be understood that the stacking rings and nestable structures of this invention can be located at the mouth of the cup, at any point along the side wall, or at any point on the bottom or projection therefrom if so desired.

In a specific example of the preferred embodiment of this invention, :1 7-ounce cup is used as shown in FIG. 1 having an average wall thickness of 0.010 inch with :1 rolled over rim 29 having an axial extent less than the axial extent of the stacking ring 13. The cup has a height of 3 /2 inches, a top inner diameter of 2 /2 inches and a bottom diameter of 1% inches at shelf 15. The internal shoulders extend inwardly approximately A inch and each has a circumferential extent of approximately inch. Six protuberances 18 are provided defining external lower shoulders 17 each having a circumferential extent of W inch. Lines 19 lie at 20 angles to the vertical axial length and the stacking ring is X inch. When a plurality of cups as above described are stacked, jamming is avoided in normal usage and when destructive forces are applied, no interlocking of the cups occurs although collapsing of the ends is sometimes evidenced.

Turning now to another embodiment of a stacking means in accordance with the present invention, a thin wall, thermoformed plastic cup 40 is illustrated in FIGS. 7-9A wherein like reference numerals refer to like components of the cup 10 described above. The cup 40 is generally identical to the cup 10 except that the stacking ring 13 is modified so that the protuberances 18 are spaced closer together and are substantially adjacent at their bases so that spaces 17a become points. In addition, recesses or inward projections 41 are provided at equally spaced intervals extending above spaced internal shoulders 16. These recesses 41 shown in cross section in FIG. 9A provide for positive air passage between the bottom of one cup and the upper portion thereof when the cups are stacked as shown in FIG. 8. In addition, the projections 41 define sliding surfaces 42 which act as cam means to center a cup when placed within another cup. Thus the external shoulders 17 slide down the wall 42 shown in FIG. 9A and are centered when placed above the internal shoulders 16 of an underlying cup. The surfaces 42 cushion the inner cup and preferably act as a shock absorbing means when the base portions 43 lie on a circle having a diameter slightly smaller than the utside diameter of a circle defined by edges of shoulders 17.

Three recesses 41 are used in cup spaced uniformly apart about the 360 circumference of the cup; however, the number of recesses can vary although when used, preferably three to six recesses are provided.

The embodiment shown in FIGS. l0l2 is again basically similar to that described with reference to FIG. 1. Cup is identical to cup 10 and like parts are indicated by like reference numerals. The difference lies in the stacking ring 113 of the cup 50 which has the same function as stacking ring 13. In connection with the stacking ring, portions similar to stacking ring 13 are denoted by adding a l in front of the numbers indicated for those portions in stacking ring 13. Protuberances 118 formed by separate portions 118a and 1181) are provided adjacent the bottom wall 12 of the cup of define upper internal shoulders 116 which are circumferentially undercut and extend circumferentially as do interrupted gaps or spaces 116a. Because of the reverse left and right helical directions of adjacent protuberance portions 118a and 11812, internal shoulders such as 16 of FIG. 1 are separated by what is termed here subinternal shoulders 116k which are not undercut and which interrupt gaps 116a as best shown in FIG. 12. Similarly the lower shoulders 117 are interrupted by subgaps or subspaces 117k and are spaced from each other by lower spaces 117a which correspond to spaces 17a. In this embodiment, recessed portions 11317 and 113a of cylindrical portions of the stacking ring form successive alternately inverted trapezoids about the circumference of the cup as viewed in FIGS. 10 and 11. The interrupted protuberances 118 are delimited by lines 119 on either side thereof which define alternate reverse helical lines in the stacking ring to provide undercuts 11% as indicated in FIG. 12 for the upper internal shoulders 116.

In the embodiment of cup 50, the same principle previously used has again been provided undercut areas as above described in a circumferential direction rather than a radial direction to provide a circumferential interference for external shoulders. In this case, each interrupted protuberance has side lines 119 which define portions of helices drawn about the central axis of the cup with alternate helical portions being reversed from left to right to prevent threading of one cup within another. Actually each interrupted protuberance is formed by a set of reverse helically extending columns of smaller protuberances extending on reverse helices.

In still another embodiment of the invention, a conical cup is provided with a stacking ring 213 generally similar to the stacking ring described with reference to FIGS. 10-12. In this embodiment, as in the embodiment of FIG. 10, the stacking portions similar to stacking ring 13 are denoted by adding a 2 in front of the numbers indicated for those portions in stacking ring 13. The cup 60 is a conventional conical cup having a side wall 11 defining an upper generally cylindrical slightly conical section and a lower conical section joined to the upper section. A conventional rolled over rim 29 is provided having an axial extent less than the axial extent of the stacking ring 213 similar to the other embodiments of this invention. In this embodiment, a lower cylindrical portion 61 is joined to the stacking ring 13 and lies above a conical-shaped portion 62 and flat bottom 63. Portions 61 and 62 are useful for engaging the cup 60 with a conventional conical cup holder as is known in the art.

The stacking ring 213 is generally similar to the stacking ring 113 except that the protuberances are spaced in four groups as best seen in FIG. 14 with the protuberances 218 being interrupted by spaces 213a. Alternate cylindrical portions of the stacking ring 213 denoted at 2131b correspond to portions 13b and are nonuniform in size due to the spacing of the protuberances. Recessed portions 2131; provide internal shoulders 216 which are alternately nonuniform in circumferential length and subinternal shoulders 216b equivalent to shoulders 1161).

The interrupted protuberances 218 are formed in the same manner as the interrupted protuberances of the embodiment of FIG. 10 to define interrupted upper gaps and interrupted lower shoulders as previously described.

Turning now to the sketches shown in FIGS. 16-18, the circumferential extent of the upper shoulders, spaces, lower shoulders and spaces, are indicated to show corresponding parts in each of the embodiments of this invention, FIGS. 16-18 more clearly indicate the fact that each lower or external shoulder whether it be interrupted or continuous, has a greater circumferential extent than each gap defined between the upper or internal shoulders, whether it be continuous or interrupted. Thus, in FIG. 16, which is a flattened strip of stacking ring 13, each length of external shoulders 17 is greater than each gap or space 16a. Similarly, in FIG. 17, showing stacking ring 113, each external shoulder 117 even though it be interrupted by subgaps 11% is greater than each interrupted space 116a. In FIG. 18, each external shoulder 217 formed by two protuberance portions on the circumference of the stacking ring 213, defines a circumferential extent greater than each gap 216a.

In the embodiments of FIGS. 19 and 20, the broadest aspect of the present invention is illustrated wherein a stacking ring is used having a single protuberance which provides a single circumferentially undercut shelf which is preferably horizontal as is shelf 15. In this embodiment, the cup is provided with a cylindrical stacking ring 313 preferably defining a right cylinder coaxial with the axis 314 of the cup. Cup bottom 312 extends across the stacking ring. Extending from top to bottom of the stacking ring is a single protuberance 318 generally similar to the protuberances 18 described above. Thus, a single internal shoulder 316 is provided interrupted at one point by gap 316a. The shoulder 316 is undercut due to the angular arrangement of lines 319 which define the intersection of the protuberance with the cylindrical stacking ring and preferably lie on uniformly inclined helical portions coaxial with the axis 314.

As can be determined from the drawings, in this embodiment the single lower external shoulder 317 does not have a circumferental length any greater than the single upper internal gap 316a and shoulder 316 and gap 317a have exactly the same circumferential length since the lines 319 are parallel to each other. However since there is a circumferential undercut underlying the internal shoulder 316 formed by the protuberance 318, when two like cups are stacked, and pressed together in an axial direction, the cups will nest and the inner cup will not move beyond the stacking ring shelf provided by the single internal shoulder 316. However, the inner cup will move beyond the shelf only if one cup is rotated with respect to its axis so as to screw thread into the other. The only bar to screw threading is stock thickness; however, inherent flexibility of the thin side wall permits somestretching and allows screw threading, Here again, no radially extending undercut is provided and only a circumferential undercut is used; yet, nesting can be accomplished. Moreover, when interlocking means are used on the cup side wall or bottom to prevent rotation of one cup with respect to another, there is no chance of an inner cup passing beyond a selected point of an outer cup. Of course, a plurality of protuberances 318 can be used in the cup 17 or if desired, alternately reversed angled protuberances 118 can be used to prevent screw threading of one cup into another.

While specific embodiments of the present invention have been shown and described, it should be understood that many variations thereof are possible. For example, any number of protuberances such as 18, 118, 218 and 318 can be used depending upon the size of the cup and the amount of interference desired. It is preferred to maximize the undercut area in order to provide maximized interference as by increasing the angles of lines 19, 119 and 219 from the vertical and/or providing many protuberances. The stacking ring structures of this invention are preferably located at the cup bottom but can be provided at any point along the side walls or at a central or other projection from the cup bottom. The number of protuberances can be varied as can their cross section configuration taken on a horizontal plane with the cup upright. It should be understood that although the protuberances have been described as extending outwardly from the cylindrical stacking ring, circumferential undercuts can also be provided by protuberances which extend inwardly of the stacking ring and should be considered the full equivalent of the embodiments described and claimed. The spacing, size and shape of protuberances in any one cup can vary. Although the side lines of each protuberance are each stated to lie on portions of a helix, it should be understood that the term helix is used to best clarify the invention and the lines may not be portions of true helices. The angle from the vertical or cup axis of the side lines is a feature in providing a circumferential undercut. The term circumferential undercut is meant to indicate a non-inwardly extending undercut but rather one that extends arcuately from side to side of a radius or about the circumference of a ring. While generally cylindrical containers have been described and a stacking ring referred to, it should be understood that the stacking ring of this invention need not be circular, and square or other shaped containers can be modified to incorporate the stacking ring of this invention. In addition the stacking ring structures of this invention are useful in lids and other devices or articles to be stacked or nested.

What is claimed is:

1. A thin wall, integral, plastic container having an upwardly flared side wall and a transversely extending bottom wall,

said container having a vertical axis in an upright position,

an inwardly extending shelf defined by at least one internal shoulder dimensioned to provide circumferential interference to a like container nested in said container with each internal shoulder having a predetermined circumferential length,

a stacking ring extending coaxially with said container and downwardly from said internal shoulder,

said stacking ring having at least two protuberances each defining side lines on said stacking ring extending from top to bottom thereof and defining a circumferential gap in said shelf at the top of said protuberances between outer side lines thereof and further defining a lower interrupted external shoulder having a greater circumferential length than the length of said circumferential gap,

said side lines of each said protuberance lie on helices with the helices of one protuberance being reversely extending with respect to the helices of the other protuberance.

2. A thin wall, integral, plastic container in accordance with claim 1 wherein said stacking ring defines a right cylindrical wall.

3. A thin wall, integral, plastic container having an upwardly flared side Wall and a transversey extending bottom wall,

said container having a vertical axis in an upright position,

an inwardly extending shelf defined by at least one internal shoulder dimensioned to provide circumferential interference to a like container nested in said container With each internal shoulder having a predetermined circumferential length,

a stacking ring extending coaxially with said container and downwardly from said internal shoulder. said stacking ring having at least two protuberances each defining side lines on said stacking ring extending from top to bottom thereof and defining an interrupted circumferential gap in said shelf at the top of said protuberances between outer side lines thereof and further defining a lower interrupted external shoulder having a greater circumferential length than the length of said circumferential gap,

said side lines of each said protuberance lying on helices with the helices of one protuberance being reversely extending with respect to the helices of the other protuberance.

4. A thin wall, integral, plastic container in accordance with claim 3 wherein said stacking ring defines a right cylindrical wall.

References Cited UNITED STATES PATENTS 3,045,887 7/1962 Caine 220-97 X 3,083,888 2/1963 Miller 229-l.5 3,091,360 5/1963 Edwards 220-97 3,353,707 11/1967 Eyles 229-15 FOREIGN PATENTS 254,306 10/ 1964 Australia.

GEORGE F. LOWRANCE, Primary Examiner US. Cl. X.R. 229l.5 

